Use simplified zipkin v2 span format

Libraries are slowly migrating over to a next version span format. The
new format is a lot easier to implement and understand.

More info: openzipkin/zipkin#1499

README.md

@@ -2,6 +2,10 @@
 
 OpenTracing Tracer implementation for Zipkin in Ruby
 
+## Requirements
+
+Zipkin version >= 2.0.0
+
 ## Installation
 
 Add this line to your application's Gemfile:

lib/zipkin/collector.rb

@@ -18,37 +18,28 @@ def send_span(span, end_time)
       finish_ts = Timestamp.create(end_time)
       start_ts = Timestamp.create(span.start_time)
       duration = finish_ts - start_ts
-      is_server = %w[server consumer].include?(span.tags['span.kind'] || 'server')
 
       @buffer << {
         traceId: span.context.trace_id,
         id: span.context.span_id,
         parentId: span.context.parent_id,
         name: span.operation_name,
+        kind: (span.tags['span.kind'] || 'SERVER').upcase,
         timestamp: start_ts,
         duration: duration,
-        annotations: LogAnnotations.build(span, @local_endpoint) + [
-          {
-            timestamp: start_ts,
-            value: is_server ? 'sr' : 'cs',
-            endpoint: @local_endpoint
-          },
-          {
-            timestamp: finish_ts,
-            value: is_server ? 'ss' : 'cr',
-            endpoint: @local_endpoint
-          }
-        ],
-        binaryAnnotations: build_binary_annotations(span)
+        debug: false,
+        shared: false,
+        localEndpoint: @local_endpoint,
+        remoteEndpoint: Endpoint.remote_endpoint(span),
+        annotations: LogAnnotations.build(span),
+        tags: build_tags(span)
       }
     end
 
     private
 
-    def build_binary_annotations(span)
-      span.tags.map do |name, value|
-        { key: name, value: value.to_s }
-      end
+    def build_tags(span)
+      span.tags.map { |key, value| [key.to_s, value.to_s] }.to_h
     end
 
     class Buffer

lib/zipkin/collector/log_annotations.rb

@@ -1,12 +1,11 @@
 module Zipkin
   class Collector
     module LogAnnotations
-      def self.build(span, endpoint)
+      def self.build(span)
         span.logs.map do |log|
           {
             timestamp: Timestamp.create(log.fetch(:timestamp)),
-            value: format_log_value(log),
-            endpoint: endpoint
+            value: format_log_value(log)
           }
         end
       end

lib/zipkin/endpoint.rb

@@ -7,11 +7,53 @@ class Endpoint
       Socket.ip_address_list.reverse.detect(&:ipv4?)
     ).ip_address
 
+    module SpanKind
+      SERVER = 'server'.freeze
+      CLIENT = 'client'.freeze
+      PRODUCER = 'producer'.freeze
+      CONSUMER = 'consumer'.freeze
+    end
+
+    module PeerInfo
+      SERVICE = 'peer.service'.freeze
+      IPV4 = 'peer.ipv4'.freeze
+      IPV6 = 'peer.ipv6'.freeze
+      PORT = 'peer.port'.freeze
+
+      def self.keys
+        [SERVICE, IPV4, IPV6, PORT]
+      end
+    end
+
     def self.local_endpoint(service_name)
       {
         serviceName: service_name,
         ipv4: LOCAL_IP
       }
     end
+
+    def self.remote_endpoint(span)
+      tags = span.tags
+      kind = tags['span.kind'] || SpanKind::SERVER
+
+      case kind
+      when SpanKind::SERVER, SpanKind::CLIENT
+        return nil if (tags.keys & PeerInfo.keys).empty?
+
+        {
+          serviceName: tags[PeerInfo::SERVICE],
+          ipv4: tags[PeerInfo::IPV4],
+          ipv6: tags[PeerInfo::IPV6],
+          port: tags[PeerInfo::PORT]
+        }
+      when SpanKind::PRODUCER, SpanKind::CONSUMER
+        {
+          serviceName: 'broker'
+        }
+      else
+        warn "Unkown span kind: #{kind}"
+        nil
+      end
+    end
   end
 end

lib/zipkin/json_client.rb

@@ -7,7 +7,7 @@ class JsonClient
     def initialize(url:, collector:, flush_interval:, logger: Logger.new(STDOUT))
       @collector = collector
       @flush_interval = flush_interval
-      @spans_uri = URI.parse("#{url}/api/v1/spans")
+      @spans_uri = URI.parse("#{url}/api/v2/spans")
       @logger = logger
     end
 

script/create_trace

@@ -12,7 +12,9 @@ tracer2 = Zipkin::Tracer.build(url: url, service_name: 'downstream-service')
 
 outer_span = tracer1.start_span(
   'receive request',
-  tags: { 'span.kind' => 'server' }
+  tags: {
+    'span.kind' => 'server'
+  }
 )
 sleep 1
 

spec/zipkin/collector/log_annotations_spec.rb

@@ -2,27 +2,24 @@
 
 RSpec.describe Zipkin::Collector::LogAnnotations do
   let(:span) { Zipkin::Span.new(nil, 'operation_name', nil) }
-  let(:endpoint) { 'local-endpoint' }
 
   context 'when log includes only event and timestamp' do
     it 'uses event as the annotation value' do
       message = 'some message'
       span.log_kv(event: message)
-      expect(described_class.build(span, endpoint)).to include(
+      expect(described_class.build(span)).to include(
         timestamp: instance_of(Integer),
-        value: message,
-        endpoint: endpoint
+        value: message
       )
     end
   end
 
   context 'when log includes multiple fields' do
     it 'converts fields into string form' do
       span.log_kv(foo: 'bar', baz: 'buz')
-      expect(described_class.build(span, endpoint)).to include(
+      expect(described_class.build(span)).to include(
         timestamp: instance_of(Integer),
-        value: 'foo=bar baz=buz',
-        endpoint: endpoint
+        value: 'foo=bar baz=buz'
       )
     end
   end

spec/zipkin/endpoint_spec.rb

@@ -0,0 +1,81 @@
+require 'spec_helper'
+
+RSpec.describe Zipkin::Endpoint do
+  let(:span) { Zipkin::Span.new(nil, 'operation_name', nil) }
+
+  shared_examples 'a rpc endpoint' do
+    it 'returns nil if no peer info' do
+      expect(remote_endpoint(span)).to eq(nil)
+    end
+
+    it 'includes service name' do
+      service_name = 'service-name'
+      span.set_tag('peer.service', service_name)
+      expect(remote_endpoint(span)).to include(serviceName: service_name)
+    end
+
+    it 'includes ipv4 address' do
+      ipv4 = '8.7.6.5'
+      span.set_tag('peer.ipv4', ipv4)
+      expect(remote_endpoint(span)).to include(ipv4: ipv4)
+    end
+
+    it 'includes ipv6 address' do
+      ipv6 = '2001:0db8:85a3:0000:0000:8a2e:0370:7334'
+      span.set_tag('peer.ipv6', ipv6)
+      expect(remote_endpoint(span)).to include(ipv6: ipv6)
+    end
+
+    it 'includes port' do
+      port = 3000
+      span.set_tag('peer.port', port)
+      expect(remote_endpoint(span)).to include(port: port)
+    end
+  end
+
+  describe '.remote_endpoint' do
+    context 'when span kind is undefined' do
+      it_behaves_like 'a rpc endpoint'
+    end
+
+    context 'when span kind is server' do
+      before { span.set_tag('span.kind', 'server') }
+
+      it_behaves_like 'a rpc endpoint'
+    end
+
+    context 'when span kind is client' do
+      before { span.set_tag('span.kind', 'client') }
+
+      it_behaves_like 'a rpc endpoint'
+    end
+
+    context 'when span kind is producer' do
+      before { span.set_tag('span.kind', 'producer') }
+
+      it 'returns broker as service name' do
+        expect(remote_endpoint(span)).to eq(serviceName: 'broker')
+      end
+    end
+
+    context 'when span kind is consumer' do
+      before { span.set_tag('span.kind', 'consumer') }
+
+      it 'returns broker as service name' do
+        expect(remote_endpoint(span)).to eq(serviceName: 'broker')
+      end
+    end
+
+    context 'when unknown span kind' do
+      before { span.set_tag('span.kind', 'something-else') }
+
+      it 'returns nil' do
+        expect(remote_endpoint(span)).to eq(nil)
+      end
+    end
+  end
+
+  def remote_endpoint(span)
+    described_class.remote_endpoint(span)
+  end
+end